.\"
.hys 50
.TH tac_plus.conf 5 "1 August 2013"
.\"
.SH NAME
.\"
tac_plus.conf \- tacacs+ daemon configuration file
.\"
.SH DESCRIPTION
.\"
This page is a work in progress.
.PP
.B tac_plus.conf
contains configuration information for the tac_plus (tacacs+) daemon.
.\"
.PP
Each line contains either one of the directives documented below,
white-space (blanks or tabs), or a comment.
.PP
Syntax enclosed in angle brackets (<>) below, refer to syntax documented
elsewhere in this manual page.
.\"
.SH "TOP-LEVEL DIRECTIVES"
.\"
.TP
.B #
Comments begin with a '#' character and extend to the end of the line.
Comments may appear anywhere in the configuration file.  To disable the
special meaning of the '#' character, enclose the string containing it
in double quotes ("#").
.TP
.B accounting
Only one configurable account parameter exists, the destination.
All accounting records are either written to a file,
.BR syslog(3)
at priority info, or both.
.sp
.nf
    accounting syslog;
    accounting file = <filename>
.fi
.sp
The default
.B filename
is @TACPLUS_ACCTFILE@.
.sp
Since accounting requests occur (and are serviced) asynchronously, it is
necessary to lock the accounting file so that two writers do not
simultaneously write to it.  The daemon uses
.BR fcntl(2)
to lock the file.  Although
.BR fcntl(2)
locking over NFS is supported on some implementations, it is notoriously
unreliable.  Even if it is reliable, locking is likely to be extremely
inefficient over NFS.  The file is best located on a local file system.
.\"
.TP
.B acl
If compiled with acl support (--enable-acls), Access Control Lists can be
defined to limit user's (or group's) login and/or enable access by daemon
client IP address or hostname.  An acl is referenced by its name, but must
be defined before it can be referenced.
.sp
The acl is a series of permit or deny statements applied to the source IP
address that the client used to connected to the daemon.  The first <regex>
that matches ends the evaluation and the result is the permit or deny on
left.  If no entry of the acl matches a given address, the result is an
implicit deny.
.sp
.nf
    acl = <name> {
        <permission> = <regex>

        # deny 66.1.255/24, allow all else in 66.1/16
        deny = ^66\\.1\\.255\\.
        permit = ^66\\.1\\.
        # implicit deny (ie: anything else)
    }
.fi
.sp
Briefly, if a company had all their loopback interfaces numbered from
66.1/16 (and thus all the tacacs clients are within 66.1/16), this acl
might be used to dis-allow a user to login to (or enable on) any router
whose loopback interface is in 66.1.255/24.
.sp
Note: because acls match against the daemon client's source IP address,
the client should be configured to use a stable source such as a loopback
interface.  For example:
.nf
    ip tacacs-server source-interface loopback 0
.fi
.\"
.TP
.B default authentication
By default, authentication fails for users that do not appear in the
configuration file.  This overrides that behavior, thus permitting
all authentication requests for such users.
.sp
.nf
    default authentication = file <filename>
.fi
.sp
Such users will be authentication via the <user> "DEFAULT".
.sp
Also see "user = DEFAULT", <default service>, and <default attribute>.
.\"
.TP
.B group
Analogous to a <user> and accepting the same syntax, a group provides
a template of which a <user> or another group can be a member.
.sp
.nf
    group = <name> {
        <user_decl>
    }
.fi
.sp
A group may be recursive; that is a group may be a member of one other
group (which may be a member of yet another group, and so on).
.\"
.TP
.B host
The host clause allows the configuration values noted below to be set
for the client named by IP address.  If
.B tac_plus
is started with the
.B \-L
option, the name can also be name as resolved from the address with the
.BR gethostbyaddr(3)
system call, which may be the FQDN (Fully Qualified Domain Name) if DNS
is used.  It is recommended that the IP address be used, since the
resolver can be slow to timeout when network faults exist.
.sp
.nf
    host = <IP address> {
	key = <string>
	prompt = <string>
	enable = <password_spec>
    }
.fi
.sp
key specifics the packet encryption <key> for this host.
.sp
prompt specifies the username prompt that will be presented to a user.
.\"
.TP
.B key
Specifies an encryption key used to encrypt packets between the daemon
and clients.  This key must match the key configured on the clients.
.sp
key = <string>
.sp
The double quotes are only necessary if your key contains white-space,
key-words, or special characters.
.sp
Note: encryption is highly recommended.
.\"
.TP
.B logging
Specifies the
.BR syslog(3)
facility used.
By default, logs are posted to the daemon facility.
.sp
.nf
    logging = <syslog_fac>
.fi
.\"
.TP
.B user
Define a user whose username is <name>.
.sp
.nf
    user = <name> {
        [ <default service> ]
        <user_attr>
        <svc>
    }
.fi
.sp
Note: seventeen special usernames exist: "DEFAULT", "$enable$",
and "$enabN$" (where N is a privilege level number, normally in the
range 0-15 on a Cisco).  The "$enable$" user is for backward compatibility
with previous versions of tacacs that is queried for privilege
level 15 in addition to "$enab15$".
.sp
Also see the "priv-lvl" AV pair in the "AV Pairs" section below and
the <default authentication> directive.
.\"
.TP
.B service
.nf
    user = <string> {
        [ default service = <permission> ]
        <user_attr>*
        <svc>*
    }
.fi
.sp
Also see the <default service> directive.
.\"
.PP
.\"
.SH "ADDITIONAL DIRECTIVE SYNTAX"
.\"
.TP
.B attr_value_pair
Specify an AV (Attribute Value) pair.  The "optional" keyword specifies that
the AV pair is optional.
.sp
.nf
    [ optional ] <string> = <string>
.fi
.sp
Optional AV pairs are only sent to the client if it requests them.  That is,
the client must have included the given AV pair as a mandatory or optional
pair in the request.
.sp
Some clients react incorrectly and negatively to receiving AV pairs that it
did not solicit.  Optional AV pairs should be ignored if they are not
recognized or not supported in any given context.
.sp
Also see the "Configuring Authorization" and "AV Pairs" sections below.
.\"
.TP
.B cmd_auth
Specify command authorization.
.sp
For command authorization, the device should expand all abbreviated commands
to their full names and compress adjacent white-space.
For example, when the command "config t" is entered it will be expanded
to "configure terminal".
.sp
.nf
    cmd = <string> {
        <cmd-match>
    }
.fi
.sp
.\"
.TP
.B cmd-match
Specify a command argument match.
.sp
.nf
    <permission> <regex>
    <permission> <regex>
	...
    <permission>
.fi
.sp
The <regex> matches arguments of the command <string>.  For example,
to allow show diag but no other show commands:
.sp
.nf
    cmd = show {
        permit diag
        deny
    }
.fi
.sp
The end of the <cmd-match> has an implicit <permission> determined by 
<default service>.
So, if the 'deny' had been omitted in the example above, the result of
the authorization would be the value of <default service>.
.sp
Note: 'cmd-arg' should never appear in a configuration file.
It is used internally by the daemon to construct a string
which is then matched against the regular expressions which appear
in a cmd clause in the configuration file.
.sp
Note: when a command has multiple arguments, they may be entered in
many different permutations.  It can be cumbersome to create regular
expressions which will reliably authorize commands under these
conditions.  Administrators may wish to consider other methods of
performing authorization.
.\"
.TP
.B default service
Specifies the default <permission> for service authorization.
.sp
.nf
    default service = <permission>
.fi
.sp
If omitted, the default is 'deny'.
.sp
Note: if used, <default service> must precede all other <svc> directives
in a <user> clause.
.\"
.TP
.B default attribute
Specifies the default attribute <permission> for service authorization.
.sp
.nf
    default attribute = <permission>
.fi
.sp
Note: if used, <default attribute> must precede all other <svc_attr>
directives in a <svc> clause.
.\"
.TP
.B des_string
Represents the one-way encryption of a password <string>.  For example,
a password might encrypt to the string 0AmUKnIT2gheo.
.sp
DES is the encryption historically used in Unix passwd(5) files.  The
crypt() function of the system's libcrypt is used to perform the
encryption.  The libcrypt of modern Unicies tend to support additional
encryption algorithms and thus so would
.B tac_plus.
See the system's crypt manual page.  To utilize another format, use the
des keyword followed by the crypt in the format as described in the
manpage.  Typically it will have a "$1" prefix for MD5, "$2" for blowfish,
and so on.
.sp
.BR tac_pwd (8)
is a utility supplied with
.B tac_plus
to assist in performing this encryption.
.\"
.TP
.B expires
Causes the <user>'s password to become invalid, starting on the specified
expiration date.
.sp
.nf
    expires "May 23 2005"
.fi
.sp
A expiry warning message is sent to the user at login time,
starting at 14 days before the expiration date.
.sp
If the <user>'s <login> <password_spec> is "file", the "expires" field
of the configuration file is not consulted.  Instead, the daemon
looks at the the "shell" field of the password file entry for a valid
expiration date.
.sp
If Solaris shadow password files are used for authentication, the
"expires" field of the configuration file is not consulted. The expiry
field from the shadow password file (if it exists) is used as the
expiration date.
.sp
Case is not significant.
.\"
.TP
.B filename
A <string> specifying a file located in the filesystem.
.sp
While the daemon does change directories to / (root) when it starts, it
is best to specify files by their FQPN (Fully Qualified Path Name).  That
is, a path that begins with /.  For example, /var/log/file rather
than the relative path var/log/file.
.\"
.TP
.B IP address
A <string> representing an IPv4 address in dotted-quad notation.  For
example:
.sp
.nf
    192.168.1.1
.fi
.\"
.TP
.B name
A <string> by which to refer to a configuration element, such as an <acl>
or a <group>.
.sp
In general, a <name> must be defined before it can be referenced.  For
example, before a <user> can be a specified as a member of a <group>,
the <group> has to be defined.
.\"
.TP
.B password_spec
There are five authentication mechanisms available: no password, cleartext,
DES, PAM, a file in
.BR passwd(5)
format, and skey.
.sp
.nf
    file <filename>
    cleartext <string>
    des <des_string>
    PAM
    skey
    nopassword
.fi
.sp
skey is an OTP (One Time Password) facility.  The daemon must be built
with skey (--enable-skey) support.
.sp
PAM (Pluggable Authentication Modules framework) is an authentication
mechanism (and much more) capable of various types of authentication
methods that are chosen by a configuration file.
The PAM service name is the name of tac_plus executable, normally "tac_plus".
PAM can be used only for login authentication, it is not implemented for
enable authorization, and does not support OTP-like challenge system (ie:
no additional prompting).
The daemon must be built with PAM support, which is included by default
if libpam is found.
.sp
Note: some cases of <password_spec> do not accept all of these mechanisms.
.\"
.TP
.B permission
Specifies that some match (for example a <service> or <cmd-match>) is
to be allowed or denied.
.sp
.nf
    (permit | deny)
.fi
.\"
.TP
.B proto
A protocol is a subset of a service.  Typical NAS supported values are
atalk, bap, bridging, ccp, cdp, deccp, ip, ipx, lat, lcp, multilink, nbf,
osicp, pad, rlogin, telnet, tn3270, vines, vpdn, xns, xremote, and
unknown.  Note that 'protocol' is actually an AV pair.
.\"
.TP
.B string
A series of characters, not including white-space or
.B tac_plus
key-words or special characters (ie: A-Za-z0-9_).  To include any of
those exceptions, enclose the string in double quotes ("this has whitespace").
.\"
.TP
.B svc
	XXX:
.sp
.nf
    <svc_auth> | <cmd_auth>
.fi
.sp

.\"
.TP
.B svc_auth
	XXX:
		service = ( arap | connection | exec | ppp protocol = <proto> |
			shell | slip | system | tty-daemon | <client defined> )
			{
			[ <default attribute> ]
                        <attr_value_pair>*
                    }
.sp
The service AV pair is required.
.\"
.TP
.B syslog_fac
.BR syslog(3)
normally has 16 well-known channels, called facilities.
.BR syslogd(8)
can be configured to direct each of these facilities to different files.
The facilities are named: auth, cron, daemon, local[0-7], lpr, mail,
news, syslog, user, and uucp.
.\"
.TP
.B user_attr
	XXX:
.sp
.nf
    user = bart {
        arap = cleartext "arap password"
        chap = cleartext "chap password"
        enable = <password_spec>
        pap  = cleartext "inbound pap password"
        opap = cleartext "outbound pap password"
        pap  = des <des_string>
        pap  = file <filename>
        pap  = PAM
        login = <password_spec>
        global = cleartext "outbound pap password"
    }
.fi
.sp
global specifies the authentication method for all services.  login
applies to normal logins (exec).  arap, chap, pap, and opap (outbound
PAP) service passwords may be defined separately.
.sp
NOTE: a global user password cannot be used for outbound PAP. This is
because outbound PAP is implemented by sending the password from the
daemon to the client. This is a security issue if the <key> is ever
compromised.
.sp
enable specifies the enable password.  The <password_spec> may only be
of type cleartext, des, nopassword or file.  If the daemon was compiled with
per-user enable support (--enable-uenable), the host enable password will be
evaluated iff the user does not have a personal enable password.
.sp

.sp
login
name
member	- can only be 1
default service = permit
expires "May 23 2005"
    arap = cleartext "Fred's arap secret"
    chap = cleartext "Fred's chap secret"
acl = <string>
enableacl = <string>
.sp
In the case of recursion, the first match is returned.
host enable is cleartext, des, nopassword or file only.
arap
chap
.B expires "May 23 2005"
.B login
.B member
.B password
	user_attr :=
		name     = <string> |
                         login    = <password_spec> |
                         member   = <string> |
                         expires  = <string> |
                         arap     = cleartext <string> |
                         chap     = cleartext <string> |
	#ifdef MSCHAP
                         ms-chap  = cleartext <string> |
	#endif
                         pap      = cleartext <string> |
                         pap      = des <string> |
                         pap      = file <filename> |
	#ifdef PAM
                         pap      = PAM |
	#endif
                         opap     = cleartext <string> |
                         global   = cleartext <string> |
                         msg      = <string>
                         before authorization = <string> |
                         after authorization = <string>

.\"
.SH "CONFIGURING AUTHORIZATION"
.\"
Authorizing a single session can result in multiple requests being
sent to the daemon.  For example, to authorize a dialin ppp
user for IP, the following authorization requests would be made
from the client:
.TP
1)
An initial authorization request to startup ppp from the exec,
using the AV pairs service=ppp protocol=ip, will be made (Note:
this initial request will be omitted if you are autoselecting ppp,
since username will not be known yet).
.sp
This request is really done to find the address for dumb PPP (or SLIP)
clients who cannot do address negotiation. Instead, they expect you to
tell them what address to use before PPP starts up, via a text message.
.TP
2)
Next, an authorization request is made from the PPP subsystem to
see if ppp's LCP layer is authorized. LCP parameters can be set at
this time (e.g. callback). This request contains the AV pairs
service=ppp protocol=lcp.
.TP
3)
Next an authorization request to startup ppp's IPCP layer is made
using the AV pairs service=ppp protocol=ipcp. Any parameters returned
by the daemon are cached.
.TP
4)
Next, during PPP's address negotiation phase, each time the remote
peer requests a specific address, if that address isn't in the cache
obtained in step 3, a new authorization request is made to see if the
peers requested address is allowable.  This step can be repeated
multiple times until both sides agree on the remote peer's address or
until the NAS (or client) decide they're never going to agree and they
shut down PPP instead.
.PP
As you can see from the above, a program which plans to handle
authorization must be able to handle a variety of requests and respond
appropriately.
.PP
Authorization must be configured on both the client and the daemon to
operate correctly.  By default, the client will allow everything until
configured to make authorization requests to the daemon.
.PP
With the daemon, the opposite is true; by default, the daemon will deny
authorization of anything that isn't explicitly permitted.
.PP
Authorization allows the daemon to deny commands and services outright,
or to modify commands and services on a per-user basis.  Authorization
on the daemon is divided into two separate parts: commands and services.
.PP
Authorizing:
.TP
.B commands
Exec commands are those commands which are typed at a Cisco exec
prompt. When authorization is requested by the NAS, the entire command
is sent to the daemon for authorization.
.sp
Command authorization is configured by specifying a list of <regex>s
to match command arguments and an action which is a <permission>.
.sp
The following permits user Fred to run these commands:
.sp
.nf
    telnet 131.108.13.<any number> and
    telnet 128.<any number>.12.3 and
    show <anything>
.fi
.sp
All other commands are denied (by default).
.sp
.nf
    user=fred {
        cmd = telnet {
            # permit specified telnets
            permit 131\\.108\\.13\\.[0-9]+
            permit 128\\.[0-9]+\\.12\\.3
        }
        cmd = show {
            # permit show commands
            permit .*
        }
    }
.fi
.sp
The command and arguments which the user types are matched to the
regular expressions specified in the configuration file (in order of
appearance).  The first successful match performs the associated
action (<permission>). If there is no match, the command is denied
by default.
.sp


.sp
Also see the <default authentication>, <default authorization>, <default
attribute>, and <default service> directives.
.\"
.SH "AUTHORIZATION SCRIPTS"
.\"
There are some limitations to the authorization that can be done using
a configuration file.  One solution is to arrange for the daemon to
call user-supplied programs to control authorization. These "callouts"
permit almost complete control over authorization, allowing you to
read all the fields in the authorization packet sent by the client,
including all its AV pairs, and to set authorization status and send a
new set of AV pairs to the client in response.
.PP
Pre and post authorization programs are invoked by handing the command
line to the Bourne shell. On most Unix systems, if the shell doesn't
find the specified program it returns a status of one, which denies
authorization. However, at least one Unix system (BSDI) returns a
status code of 2 under these circumstances, which will permit
authorization, and probably isn't what you intended.
.PP
Note: if your program hangs, the authorization will time out
and return an error on the client, and you'll tie up a process slot on
the daemon host, eventually running out of resources. There is no
special code to detect this in the daemon.
.PP
The daemon communicates with pre and post (before and after)
authorization programs over a pair of pipes. Programs using the
standard i/o library will use full buffering in these circumstances.
This should not be a problem, since AV pairs will be read until
end of file (EOF) is seen on input, and output will be flushed
when they exit.
.PP
Fields from the authorization packet can be supplied to the programs
as arguments on the command line by using the appropriate dollar-sign
variables in the configuration file.  These fields are:
.PP
.nf
    user    -- user name
    name    -- client/NAS name
    ip      -- client/NAS IP
    port    -- client/NAS port
    address -- user address (remote user location)
    priv    -- privilege level number (0-15)
    method  -- a digit (1-4)
    type    -- digit (1-4)
    service -- digit (1-7)
    status  -- (pass, fail, error, unknown)
.fi
.PP
Unrecognized variables will appear as the string "unknown".
.PP
AV pairs from the authorization packet are fed to the program's
standard input, one per line. The program is expected to process the
AV pairs and write them to its standard output, one per line. What
happens then is determined by the exit status of the program.
.PP
Note: when AV pairs containing spaces are listed in the
configuration file, you need to enclose them in double quotes so that
they are parsed correctly. AV pairs which are returned via standard
output do not need delimiters and so should not be enclosed in double
quotes.
.PP
Note: unless special arrangements are made, the daemon will run as root
and hence the programs it invokes will also run as root, which is a
security weakness. It is strongly recommended that FQPNs are used
when specifying programs to execute, and that the daemon is compiled
with unprivileged user and group IDs (--with-userid and --with-groupid)
so that the daemon is not running as root when calling these programs,
.PP
Calling scripts
.TP
.B before authorization
Specify a per-user program to be called before any other
authorization attempt is made by using a "before" clause.
.sp
.nf
    user = auth1 {
        before authorization "/path/pre_authorize $user $port $address"
    }
.fi
.sp
The AV pairs sent from the NAS will be supplied to the program
standard input, one pair per line.
.sp
If the program returns a status of 0, authorization is unconditionally
permitted. No further processing is done on this request and no AV
pairs are returned to the client.
.sp
If the program returns a status of 1, authorization is unconditionally
denied. No further processing is done on this request and no AV pairs
are returned to the client.
.sp
If the program returns a status of 2, authorization is permitted.  The
program is expected to modify the AV pairs that it receives on its
standard input (or to create entirely new ones) and to write them, one
per line, to its standard output. The new AV pairs will be sent to the
client with a status of AUTHOR_STATUS_PASS_REPL.  No further processing
takes place on this request.
.sp
If the program returns a status of 3, authorization is denied, but all
attributes returned by the program via stdout are returned to the
client. Also, whatever the program returns on stderr is placed into the
server-msg field and returned to the client.
.sp
Any other status value returned from the program will cause an error
to be returned to the client.
.sp
Note: a status of 2 is not acceptable when doing command authorization.
.\"
.TP
.B after authorization
Specify a per-user program to be called after authorization
processing has been performed by the default, but before the
authorization status and AV pairs have been transmitted to the
client, by using a "after" clause.
.sp
.nf
    group = auth1 {
        after authorization "/path/post_authorize $user $port $status"
    }
.fi
.sp
The AV pairs resulting from the authorization algorithm that the
daemon proposes to return to the NAS, are supplied to the program on
standard input, one AV pair per line, so they can be modified if
required.
.sp
The program is expected to process the AV pairs and write them to its
standard output, one per line. What happens then is determined by the
exit status of the program:
.sp
If the program returns a status of 0, authorization continues as if
the program had never been called.  Use this if (for example) to just
send mail when an authorization occurs, without otherwise affecting
normal authorization.
.sp
If the program returns a status of 1, authorization is unconditionally
denied. No AV pairs are returned to the NAS. No further authorization
processing occurs on this request.
.sp
If the program returns a status of 2, authorization is permitted and
any AV pairs returned from the program on its standard output are sent
to the NAS in place of any AV pairs that the daemon may have
constructed.
.sp
Any other value will cause an error to be returned to the NAS by the
daemon.
.PP
Current attributes are:
.sp
.nf
    "unknown"
    "service"
    "start_time"
    "port"
    "elapsed_time"
    "status"
    "priv_level"
    "cmd"
    "protocol"
    "cmd-arg"
    "bytes_in"
    "bytes_out"
    "paks_in"
    "paks_out"
    "address"
    "task_id"
    "callback-dialstring"
    "nocallback-verify"
    "callback-line"
    "callback-rotary"
.fi
.sp
Also see the "AV Pairs" section below.
.\"
.SH "AV PAIRS"
.\"
AV (Attribute Value) pairs are text strings exchanged between the client
and server of the form "attribute=value".  The value may not appear in
authorization request packets, indicating that it is null or unspecified.
The equal sign ('=') means that this is a mandatory attribute.  An asterisk
('*') may appear in place of the equal sign, indicating that it is an
optional attribute which either the client or server may not understand or
may ignore.
.PP
Optional attributes are preceded by the "optional" key-word in the
configuration.  For example:
.sp
.nf
    priv_lvl = 15
    optional allow-shell = true

    service=ppp
    protocol=ip
    addr*131.108.12.44
.fi
.\"
.PP
The following AV pairs specify which service is being authorized. They
are typically accompanied by protocol AV pairs and other, additional
pairs from the lists below.
.sp
.TP 20
service=arap
.TP
service=shell
for exec startup, and also for command authorizations.  Requires:
.sp
.nf
    aaa authorization exec tacacs+
.fi
.TP
service=ppp
.TP
service=slip
.TP
service=system
not used.
.TP
service=raccess
Used for managing reverse telnet connections e.g.
.sp
.nf
    user = jim {
        login = cleartext lab
        service = raccess {
            port#1 = clientname1/tty2
            port#2 = clientname2/tty5
        }
    }
.fi
.sp
Requires IOS configuration
.sp
.nf
    aaa authorization reverse-access tacacs+
.fi
.\"
.\"
.PP
.TP 20
protocol=lcp
The lower layer of PPP, always brought up before IP, IPX, etc.
is brought up.
.TP
protocol=ip
Used with service=ppp and service=slip to indicate which
protocol layer is being authorized.
.TP
protocol=ipx
Used with service=ppp to indicate which protocol layer is being authorized.
.TP
protocol=atalk
with service=ppp or service=arap
.TP
protocol=vines
For vines over ppp.
.TP
protocol=ccp
Authorization of CCP.  Compression Control Protocol). No other
AV-pairs associated with this.
.TP
protocol=cdp
Authorization of CDP (Cisco Discovery Protocol). No other
av-pairs associated with this.
.TP
protocol=multilink
Authorization of multilink PPP.
.TP
protocol=unknown
For undefined/unsupported conditions. Should not occur under
normal circumstances.
.PP
Incomplete list of Cisco AV pairs.  Other vendors may provide
additional AV pairs specific to their products.
.sp
.\"
.TP
acl
For EXEC authorization this contains an access-class number (acl=2)
which is applied to the line (tty) as the output access class.  The
specified access-list must be predefined.
.sp
ARAP, EXEC.
.\"
.TP
addr
The IP address the remote host should be assigned when a slip
or PPP/IP connection is made.  For example: addr=1.2.3.4
.sp
SLIP, PPP/IP.
.\"
.TP
autocmd
During exec startup, this specifies an autocommand, like the
autocommand option to the username configuration command.  For
example: autocmd="telnet foo.com"
.sp
EXEC.
.\"
.TP
callback-line
The number of a TTY line to use for the callback.  Used with service=arap,
slip, ppp, or shell.  Does not work for ISDN.
.\"
.TP
callback-rotary
The number of a rotary group (0 through 100) to use for the callback.
Used with service=arap, slip, ppp, and shell.  Does not work for ISDN.
.\"
.TP
cmd
If the value of cmd is NULL (cmd=), then this is an authorization
request for starting an exec.
.sp
If cmd is non-null, this is a command authorization request.  It
contains the name of the command being authorized.  For example: cmd=telnet
.sp
EXEC.
.\"
.TP
cmd-arg
During command authorization, the name of the command is given
by an accompanying "cmd=" AV pair, and each command argument
is represented by a cmd-arg AV pair e.g. cmd-arg=archie.sura.net
.sp
NOTE: 'cmd-arg' should never appear in a configuration file.
It is used internally by the daemon to construct a string
which is then matched against the regular expressions which appear
in a cmd clause in the configuration file.
.sp
EXEC.
.\"
.TP
dns-servers
Identifies a primary or backup DNS server that can be requested by
Microsoft PPP clients during IPCP negotiation.  Used with service=ppp and
protocol=ip.
.\"
.TP
gw-password
Specifies the password for the home gateway during L2F tunnel authentication.
Used with service=ppp and protocol=vpdn.
.\"
.TP
idletime
Sets a value, in minutes, after which an IDLE session will be
terminated.  Does NOT work for PPP.
.sp
EXEC, 11.1 onward.
.\"
.TP
inacl
This AV pair contains an IP or IPX input access list number
for slip or PPP (inacl=2). The access list itself must be
pre-configured on the Cisco box. Per-user access lists do not
work with ISDN interfaces unless you also configure a virtual
interface. After 11.2(5.1)F, you can also use the name of a
predefined named access list, instead of a number, for the
value of this attribute.
.sp
Note: For IPX, inacl is only valid after 11.2(4)F.
.sp
PPP/IP/IPX.
.\"
.TP
inacl#<n>
This AV pair contains the definition of an input access list
to be installed and applied to an interface for the duration
of the current connection, e.g.
.sp
.nf
    inacl#1="permit ip any any precedence immediate"
    inacl#2="deny igrp 0.0.1.2 255.255.0.0 any"
.fi
.sp
Attributes are sorted numerically before they are applied.
For IP, standard OR extended access list syntax may be used,
but it is an error to mix the two within a given access-list.
.sp
For IPX, only extended access list syntax may be used.
.sp
PPP/IP/PPP/IPX, 11.2(4)F.
.\"
.TP
interface-config
Specifies user-specific AAA interface configuration information with
Virtual Profiles.  The information that follows the equal sign (=) can
be any Cisco IOS interface configuration command.
.\"
.TP
ip-address
List of possible IP addresses, separated by spaces, that can be used for
the end-point of a tunnel.  Used with service=ppp and protocol=vpdn.
.\"
.TP
link-compression
Defines whether to turn on or turn off Stac compression over a PPP link.
Valid values are:
.sp
.nf
	0	None
	1	Stac
	2	Stac Draft-9
	3	MS-Stac
.fi
.\"
.TP
load-threshold
This AV pair sets the load threshold at which an additional
multilink link is added to the bundle (if load goes above) or
deleted (if load goes below).
.sp
.nf
    service=ppp protocol=multilink {
        load-threshold=<n>
    }
.fi
.sp
The range of <n> is [1-255].
.sp
PPP/multilink - Multilink parameter, 11.3.
.\"
.TP
max-links
This AV pair restricts the number of multilink bundle links
that a user can have.
.sp
.nf
    service=ppp protocol=multilink {
        max-links=<n>
    }
.fi
.sp
The range of <n> is [1-255].
.sp
PPP/multilink, 11.3.
.\"
.TP
nas-password
Specifies the password for the NAS during L2F tunnel authentication.
Used with service=ppp and protocol=vpdn.
.\"
.TP
nocallback-verify
Indicates that no callback verification is required. The only
valid value for this parameter is the digit one,  i.e.
nocallback-verify=1.  Not valid for ISDN.
ARAP/EXEC, 11.1 onward.
.\"
.TP
noescape
During exec startup, this specifies "noescape", like the
noescape option to the username configuration command.  Can
have as its value the string "true" or "false".  For example: noescape=true
.sp
EXEC.
.\"
.TP
nohangup
During exec startup, this specifies "nohangup", like the
nohangup option to the username configuration command.  Can
have as its value the string "true" or "false".  For example:
nohangup=true
.sp
EXEC.
.\"
.TP
old-prompts
Allows the prompts in TACACS+ to appear identical to those of earlier
systems (TACACS and Extended TACACS).  This allows the upgrade from TACACS
or Extended TACACS to TACACS+ to be transparent to users.
.\"
.TP
outacl
This AV pair contains an IP or IPX output access list number
for SLIP. PPP/IP or PPP/IPX connections (outacl=4). The
access list itself must be pre-configured.
Per-user access lists do not work with ISDN interfaces
unless you also configure a virtual interface.  PPP/IPX is
supported in 11.1 onward only. After 11.2(5.1)F, you can also
use the name of a predefined named access list, as well as a
number, for the value of this attribute.
.sp
PPP/IP, PPP/IPX.
.\"
.TP
outacl#<n>
This AV pair contains an output access list definition to be
installed and applied to an interface for the duration of the
current connection.
.sp
.nf
    outacl#1="permit ip any any precedence immediate"
    outacl#2="deny igrp 0.0.9.10 255.255.0.0 any"
.fi
.sp
Attributes are sorted numerically before they are applied.
For IP, standard OR extended access list syntax may be used,
but it is an error to mix the two within a given access-list.
.sp
For IPX, only extended access list syntax may be used.
.sp
PPP/IP/PPP/IPX, 11.2(4)F.
.\"
.TP
pool-def#
Defines IP address pools on the NAS.  Used with service=ppp and protocol=ip.
.\"
.TP
pool-timeout
In conjunction with pool-def, defines IP address pools on the NAS.  During
IPCP address negotiation, if an IP pool name is specified for a user (see
the addr-pool attribute), a check is made that the named pool is defined on
the NAS.  If it is, the pool is consulted for an IP address.
.\"
.TP
ppp-vj-slot-compression
Instructs the Cisco router not to use slot compression when sending
VJ-compressed packets over a PPP link.
.\"
.TP
priv-lvl
Specifies the current privilege level for command
authorizations, a number from zero to 15.  For example: priv_lvl=5.
.sp
Note: in 10.3 this attribute was priv_lvl, i.e.
it contained an underscore instead of a hyphen.
.sp
EXEC.
.\"
.TP
route
This AV pair specifies a temporary static route to be applied, which
expunged once the connection terminates.  The daemon side declaration is:
.sp
.nf
    service=ppp protocol=ip {
        route="<dst_addr> <mask> [ <gateway> ]"
    }
.fi
.sp
<dst_address>, <mask>, and <gateway> are <IP address>'s.  If the
gateway is omitted, the peer's address is assumed.
.sp
PPP/IP/SLIP, 11.1 onward.
.\"
.TP
route#<n>
Same as the "route" attribute, except that these are valid for
IPX as well as IP, and they are numbered, allowing multiple
routes to be applied.  For example:
.sp
.nf
    route#1="3.0.0.0 255.0.0.0 1.2.3.4"
    route#2="4.0.0.0 255.0.0.0"
.fi
.sp
or, for IPX,
.sp
.nf
    route#1="4C000000 ff000000 30.12.3.4"
    route#2="5C000000 ff000000 30.12.3.5"
.fi
.sp
PPP/IP/IPX, 11.2(4)F.
.\"
.TP
routing
Equivalent to the /routing flag in slip and ppp commands. Can
have as its value the string "true" or "false".
.sp
SLIP/PPP/IP.
.\"
.TP
rte-ftr-in#
Specifies an input access list definition to be installed and applied to
routing updates on the current interface for the duration of the current
connection.  Used with service=ppp protocol=ip or protocol=ipx.
.\"
.TP
rte-ftr-out#
Output version of rte-ftr-in#.
.\"
.TP
sap#<n>
This AV pair specifies static SAPs (Service Advertising Protocol) to be
installed for the duration of a connection.  For example:
.sp
.nf
    sap#1="4 CE1-LAB 1234.0000.0000.0001 451 4"
    sap#2="5 CE3-LAB 2345.0000.0000.0001 452 5"
.fi
.sp
The syntax of static saps is the same as that used by the IOS "ipx sap"
command.  Used with service=ppp protocol=ipx.
.sp
PPP/IPX, 11.2(4)F.
.\"
.TP
sap-fltr-in#<n>
This AV pair specifies an input SAP filter access list definition to be
installed and applied to the current interface, for the duration of the
current connection.
.sp
Only Cisco extended access list syntax is legal (ipx input-sap-filter
<number>).  For example:
.sp
.nf
    sap-fltr-in#1="deny 6C01.0000.0000.0001"
    sap-fltr-in#2="permit -1"
.fi
.sp
Attributes are sorted numerically before being applied.  Used with
service=ppp protocol=ipx.
.sp
PPP/IPX, 11.2(4)F.
.\"
.TP
sap-fltr-out#<n>
This AV pair specifies an output sap filter access list definition to be
installed and applied on the current interface, for the duration of the
current connection.
.sp
Only Cisco extended access list syntax is legal (ipx output-sap-filter
<number>), e.g
.sp
.nf
    sap-fltr-out#1="deny 6C01.0000.0000.0001"
    sap-fltr-out#2="permit -1"
.fi
.sp
Attributes are sorted numerically before being applied.  Used with
service=ppp protocol=ipx.
.sp
PPP/IPX, 11.2(4)F.
.\"
.TP
source-ip
This specifies a single ip address that will be used as the source of
all VPDN packets generated as part of the VPDN tunnel (see the
equivalent source-ip keyword in the IOS vpdn outgoing command).
.sp
PPP/VPDN, now deprecated, only existed in releases 11.2(1.4) thru 11.2(4.0.2).
.\"
.TP
timeout
Sets the time until an ARAP or exec session disconnects unconditionally
(in minutes).  For example: timeout=60
.sp
ARAP/EXEC, 11.0 onward.
.\"
.TP
tunnel-id
This AV pair specifies the username that will be used to
authenticate the tunnel over which the individual user MID
will be projected.  This is analogous to the "NAS name" in
the "vpdn outgoing" command.
.sp
PPP/VPDN, 11.2 onward.
.\"
.TP
zonelist
An Appletalk zonelist for arap (ARAP) equivalent to the line
configuration command "arap zonelist".  For example: zonelist=5.
.PP
AV pairs reserved for future use (this list may be out-dated):
.sp
.nf
    ppp-vj-slot-compression
    link-compression
    asyncmap
    x25-addresses (PPP/VPDN)
    frame-relay (PPP/VPDN)
.fi
.PP
Note: this AV pair list is NOT complete and not all AV pairs are supported
by all vendors.  See the vendor's documentation.  When a client (or server)
receives a mandatory AV pair that it does not understand, the
authorization FAILS!
.sp
Also see the
.B tac_plus
user guide.  Some of the callback, appletalk, IPX, VPDN, PPP routing, and
address pool related AV pairs found in the user guide have been omitted.
.\"
.SH "ACCOUNTING AV PAIRS"
.\"
.TP 20
bytes_in
The number of input bytes transferred during this connection.
.\"
.TP
bytes_out
The number of output bytes transferred during this connection.
.\"
.TP
cmd
The command the user executed.
.\"
.TP
data-rate
This AV pair has been renamed. See nas-rx-speed.
.\"
.TP
disc-cause
Specifies the reason a connection was taken off-line.  The Disconnect-Cause
attribute is sent in accounting stop records.  This attribute also causes
stop records to be generated without first generating start records if
disconnected before authentication.
.sp
.nf
	1	User request
	2	Lost carrier
	3	Lost service
	4	Idle timeout
	5	Session timeout
	6	Admin reset
	7	Admin reboot
	8	Port error
	9	NAS error
	10	NAS request
	11	NAS reboot
	12	Port unneeded
	13	Port pre-empted
	14	Port suspended
	15	Service unavailable
	16	Callback
	17	User error
	18	Host request
.fi
.\"
.TP
disc-cause-ext
Extends the disc-cause attribute to support vendor-specific reasons that a
connection was taken off-line.
.sp
.\" XXX needs formatting help
.nf
	1000	Session timed out. This value applies to all session types.
	1002	Reason unknown.
	1004	Failure to authenticate calling-party number.
	1010	No carrier detected. This value applies to modem connections.
	1011	Loss of carrier. This value applies to modem connections.
	1012	Failure to detect modem result codes. This value applies to modem connections.
	1020	User terminates a session. This value applies to EXEC sessions.
	1021	Timeout waiting for user input. This value applies to all session types.
	1022	Disconnect due to exiting Telnet session. This value applies to EXEC sessions.
	1023	Could not switch to SLIP/PPP; the remote end has no IP address. This value applies to EXEC sessions.
	1024	Disconnect due to exiting raw TCP. This value applies to EXEC sessions.
	1025	Bad passwords. This value applies to EXEC sessions.
	1026	Raw TCP disabled. This value applies to EXEC sessions.
	1027	Control-C detected. This value applies to EXEC sessions.
	1028	EXEC process destroyed. This value applies to EXEC sessions.
	1040	PPP LCP negotiation timed out. This value applies to PPP sessions.
	1041	PPP LCP negotiation failed.
	1042	PPP PAP authentication failed.
	1043	PPP CHAP authentication failed.
	1044	PPP remote authentication failed.
	1045	PPP received a Terminate Request from remote end.
	1046	Upper layer requested that the session be closed.  This value applies to PPP sessions.
	1101	Session failed for security reasons. This value applies to all session types.
	1102	Session terminated due to callback. This value applies to all session types.
	1120	Call refused because the detected protocol is disabled. This value applies to all session types.
.fi
.\"
.TP
elapsed_time
The elapsed time in seconds for the action. Useful when the device does not
keep real time.
.\"
.TP
event
Information included in the accounting packet that describes a state change
in the router.  Events described are accounting starting and accounting
stopping.
.\"
.TP
mlp-links-max
Gives the count of links known to have been in a given multilink session at
the time the accounting record is generated.
.\"
.TP
mlp-sess-id
Reports the identification number of the multilink bundle when the session
closes.  This attribute applies to sessions that are part of a multilink
bundle.  This attribute is sent in authentication-response packets.
.\"
.TP
nas-rx-speed
Specifies the average number of bits per second over the course of the
connection's lifetime.  This attribute is sent in accounting stop records.
.\"
.TP
nas-tx-speed
Reports the transmit speed negotiated by the two modems.
.\"
.TP
paks_in
The number of input packets transferred during this connection.
.\"
.TP
paks_out
The number of output packets transferred during this connection.
.\"
.TP
port
The port into which the user was logged.
.\"
.TP
pre-bytes-in
Records the number of input bytes before authentication.  This attribute
is sent in accounting stop records.
.\"
.TP
pre-bytes-out
Records the number of output bytes before authentication.  This attribute
is sent in accounting stop records.
.\"
.TP
pre-paks-in
Records the number of input packets before authentication. This attribute
is sent in accounting stop records.
.\"
.TP
pre-paks-out
Records the number of output packets before authentication.  This attribute
is sent in accounting stop records as Pre-Output-Packets.
.\"
.TP
pre-session-time
Specifies the length of time, in seconds, from when a call first connects
to when it completes authentication.
.\"
.TP
priv_level
The privilege level associated with the action.
.\"
.TP
protocol
The protocol associated with the action.
.\"
.TP
reason
Information included in the accounting packet that describes the event that
caused a system change.  Events described are system reload, system shutdown,
or accounting reconfiguration (turned on or off).
.\"
.TP
service
The service the user used.
.\"
.TP
start_time
The time, in seconds since 12:00 a.m. January 1, 1970, that the action
started.  The clock must be configured to receive this information.
.\"
.TP
stop_time
The time, in seconds since 12:00 a.m. January 1, 1970, that the action
stopped.  The clock must be configured to receive this information.
.\"
.TP
task_id
Start and stop records for the same event must have matching (unique)
task_id numbers.
.\"
.TP
timezone
The time zone abbreviation for all timestamps included in this packet.
.\"
.TP
xmit-rate
This AV pair has been renamed nas-tx-speed.
.\"
.SH "EXAMPLE CLIENT CONFIGURATION"
.\"
Example Cisco configuration for tacacs+:
.sp
.nf
    aaa new-model
    aaa authentication login default tacacs+ local
    aaa authentication enable default tacacs+ enable
    aaa authorization exec default tacacs+
    aaa accounting exec default start-stop tacacs+
    !
    username root privilege 15 password 0 <root's password>
    !
    tacacs-server key <your key here>
    tacacs-server host <ip_address>
    ip tacacs source-interface loopback0
    !
    enable secret 0 <enable password>
.fi
.sp
Note that the aaa command syntax varies slightly between some versions
of Cisco IOS and CatOS (Catalyst OS) also varies.
.sp
Example Juniper configuration for tacacs+:
.sp
.nf
    system {
        authentication-order [ password tacplus ];
        tacplus-server {
            <ip_address> secret <your key here>;
            <ip_address> {
                secret <your key here>;
                timeout 90;
            }
        }
    }
.fi
.sp
Both of these examples are brief.  See the vendor's documentation for a
description of what these configuration commands specify and for additional
commands and arguments.
.sp
WARNING:  If not properly configured, it may not be possible to login to
the device!
.\"
.SH "EXAMPLE TAC_PLUS CONFIGURATION"
.\"
.nf
key = "your key here"
accounting file = /var/log/tac.acct
# authentication users not appearing elsewhere via
# the file /etc/passwd
default authentication = file /etc/passwd

acl = dial_only {
    # All access routers are in 192.168/16, but except for
    # 192.168.0.1 all backbone router are in 198.168.0/24.
    # deny access to the backbone routers.
    permit = ^192\\.168\\.0\\.1$
    deny   = ^192\\.168\\.0\\.
    permit = ^192\\.168\\.
}

group = no_backbone {
    # permit an exec to start and permit all commands and
    # services by default
    default service = permit

    service = exec {
        # When an exec is started, its connection access list
        # will be 4. "acl" is quoted because it is a keyword.
        # It also has an autocmd
        "acl" = 4
        autocmd = "telnet duffhost"
    }

    # group will only be allowed to login on NASes
    acl = dial_only
}
group = admin {
    # group members who don't have their own login password will be
    # looked up in /etc/passwd
    login = file /etc/passwd

    # group members who have no expiry date set will use this one
    expires = "Jan 1 1997"

    # deny access to backbone routers
    acl = dial_only
}

user = DEFAULT {
    service = ppp protocol = ip {
        addr-pool=foobar
    }
}
user = homer {
    default service = permit

    member = no_backbone
}
user = fred {
    login = des mEX027bHtzTlQ
    name = "Fred Flintstone"
    member = admin
    expires = "May 23 2005"
    arap = cleartext "Fred's arap secret"
    chap = cleartext "Fred's chap secret"

    service = exec {
        # When Fred starts an exec, his connection access
        # list is 5
        "acl" = 5

        # We require this autocmd to be done at startup
        autocmd = "telnet foo"
    }

    # All commands except show system are denied for Fred
    cmd = show {
        # Fred can run the following show command

        permit system
        deny .*
    }

    service = ppp protocol = ip {
        # Fred can run ip over ppp only if he uses one
        # of the following mandatory addresses. If he
        # supplies no address, the first one here will
        # be mandated

        addr=131.108.12.11
        addr=131.108.12.12
        addr=131.108.12.13
        addr=131.108.12.14

        # Fred's mandatory input access list number is 101
        inacl=101

        # We will suggest an output access list of 102, but the NAS may
        # choose to ignore or override it

        optional outacl=102
    }

    service = slip {
        # Fred can run slip. When he does, he will have to use
        # these mandatory access lists

        inacl=101
        outacl=102
    }
}

user = wilma {
    # Wilma has no password of her own, but she's a group member so
    # she'll use the group password if there is one. Same for her
    # password expiry date

    member = admin
}
.fi
.\"
.SH FILES
.\"
.TP 30
/etc/tac_plus.conf
Configuration file.
.\"
.TP
@TACPLUS_ACCTFILE@
The default accounting file.
.\"
.TP
@TACPLUS_LOGFILE@
The default log file.
.\"
.SH "SEE ALSO"
.\"
.BR gethostbyaddr (3),
.BR passwd (5),
.BR regexp (3),
.BR tac_plus (8),
.BR tac_pwd (8)
.PP
Also see the
.B tac_plus
User Guide (user_guide) that came with the distribution.
The user guide does not cover all the modifications to the original
Cisco version nor does this manual page cover everything that is
in the user guide (callback configuration, for example).
.\"
.SH AUTHOR
.\"
The tac_plus (tacacs+) developer's kit is a product of Cisco Systems.
Made available at no cost and with no warranty of any kind.  See the
file COPYING and source files that came with the distribution for
specifics.
.\"
.SH HISTORY
.\"
This manual page was adapted from code inspection and Cisco's
.B tac_plus
user guide.
.\"
.SH BUGS
.\"
This manual page is incomplete.
